Thermometer



Feb. 24, 1931.- M. E. MOELLER THERIOMETER Filed Dec.

INVENTOR 44: E. W

Patented Feb. 24, 1931 ."UNITED STATES (MAX ELMOELLER, on BRooxIlYmnnwYORK, ASSIGNOR, BY Mam ASSIGNMENTS, 'ro company, Inc, or nnooxm'n. new Aconronarron MOELLER INSTRUMENT or ew You PATENT OFFICE rirnnriorrn'rnaApplication filed name 11, 1923; Serial n erases.

. improvements relate to thermometers hav ng an unusually long tube orstem. Such 'thermometersare used for indicating the tem- ':perature ofliquids whilethey are being boiled or cooked or maintained in a liquidstate at I high temperaturqfor instancegin the cooking or boilingoperations of sugar juices and syrups, glue, varnish, printinginksyandin the melting of lead, type metal and other metals havinga relativelylowmelting point. As large quantities are commonly treated, the

vessels are often severall feet in depth, and as thethermometerscale,"in most cases" must "be above the topof the vessel inorder tobe easily read, the stem i of the thermometer betweenthe b'ulb'rand the scalemusthave a considerable length, often'three feet onmore.

Itisinecessaryalso in: most cases that the temperature'of the heatedliquidjbe observed throughout the cooking or heating operation, and thisrequires that the thermometer shall A presentconstruction of the stem insuch rounding the stem of the thermometer and 1 extending from-the bulbatth'e bottom rto thescale' at-thetop provided withdpacking tubebeingclosed for the purpose of excluding the heated liquid. Ithasbeenfound inprac- 351,3 tice howeverthatit isnotpossibleto securely {ct asbestosor'other insulating materiali between it and theistem, the lower endofthe sealthe lower end ofj'the tube, where the stem of the thermometer"-nearlthe bulb projects hasbeen calibrated, and'therefore to be comeinaccurate. Even before the insulating material has become saturated, itis notipossible to insure approximately accurate temperatureindications, owing to the fact that exposure of the outer tube tothehigh temperature of the liquid for any considerable period will peratureand the period ofexposure.

cause heat to radiate and be conducted to a certain extent through thepacking of insu' latlng materlal, so that the reading of the thermometerwillqvary according to the temfore, as the thermometer must becalibrated at a given temperature and period of exposure, it will bemore or less inaccurate for all other temperatures and periods. Thevariations in temperature are also affected bythe particular nature andheat conductivity of the eter stemlisimmersed therein. 1 1 1 Nor can thedifficulty be overcome by dispensing Witlrthinsulating packing, for inency, on account of its contractionand expan- .sion,t0 crack the stem.In the course of time, t also, the tubewould become partlyfilled withremain in the heatedliqui'd for a relatively 'long'period" of" time;this period running as 1 'high; as three orlfour hours in some cases.

i thermometers comprises'a tube of metal'surthe hardened substance,which would tEorma conductor of heat. In addition to this the longattenuated form of the glass'thcrnlometer stem should be supported andreinforced against shocks and vibration Within the outer tube. 1

The present improvements are designed to overcome these difliculties,and this is accomplished by first placing the thermometer stem in. ametallic tube ofrelat-ively small diameter, and then placing this tube,with the stem therein, in a much larger tube haw inglopenings at itslower part andat points higher up, through which the liquid may flowfreely intothe annular space between the two tubes so as to have accessto the inner tube and through which the liquid may escape when thethermometer is removed from the boiler or other retort, the upperopenings also serving as ventstfor vapor, steam and other. gases, andliquid mixedwith air or gas in the form of team or other form. Theimprovements therefore, instead of seeking to prevent access of theliquid to the inner tube, contemplate the tree access of the liquidthereto, and, a heating of the entire stem ot the thermometer tosubstantially the temperature of the body of liquid, thus enabling themake? to calibrate the instrument under 1101 Thereliquid, and the depthto which the thermonicondition of the other parts.

mal conditions of use, strengthening and reinforc ng the stem, andenabling him to replace the glass thermometer proper when necessaryWithout specially calibrating the newmstrument, to ad ust it to achanged The improvements also provide an instrumentwhich will give aquick reading of any temperature, and facilitate, 'cleaning of' theinstrument, by immers ng it in a "solvent fluid; This" is seldomnecessary however embodying the improvements; Fig. 2 is a side elevationthereof; and Fig. 3*is a vertical med al section' of the tubessurrounding the stem of the thermometer, with r the ther mometer andthewrapping of its stem-shown in elevation therein, parts being broken awaymedially in each iVlGW and foreshortened.

,The thermometer proper cons stsof'a stem or tube l, having a'bulb Qiat'its lower end, and a scale Withwhich its iupperend'risconnected, thesaid scalebeing in asuitablehousing provided with a hanger 5,by:which'the entire instrument; may be v handlediorsuspended. The lowertubular-extremityGof the scale housing receives the. upper- 'endof theouter tube 7, which encloses the stem, and

" is secured in said tubular portion, and on the-lower end of thistubeaprotecting cage 10 enclosing the lower end" ofthe tube'a-nd itsbulb is threaded. This is accomplished by means of a hollow plugllthreaded into the lowerend" ofthe tube 7, amt-havingthe upper endeithe -cage 10 engaging on its extube.

stripor filament 8 of asbestos or other soft insulating material,extending from endto end of its'protecting tube 9, and forming a thinspacing -cushion between the saidi stem and tube. -This cushion or anyform suitable for thepurpose, which. is

packing may have to cushion and support against vibration within thetube the stem of without insulating it to any material-extent the samemanner its lower end, and a setscrew '12 threaded into the outer tubeand having its point entering a recess in the inthreaded and engages theinteriorl'ythreaded: upper portion of the hollow plug 11, so thatv thetubes 7 and 9 are securely held in spaced 1 relation toprovide'an'annular channel-1 3bethe the-rmometer,-

tween them from end to end, in which fluid entering through the openings14 may circulate freely. Openings 15 in the tube 7 are provided at itsupper part, and through these openings fluid may also enter if theinstrument is immersed to a: suflicient-v depth,v They are intendedhowever to 'permitthe escape of vapor and gases and froth which has atendency to risein the. tube, to a considerable, distanceabovejtheleveli ofthe body ofl'iqui'd; A vent hole 1'6 is 'alsoprovidedat the top of thetube for Vapor, heated air or other gases arisingtherein. In this manner the free accessbfthafluid totheinterior of thetube and the protecting shell of the thermometer stem is providedi'forand. the communication of the heat thereof to: the entirezjlengthrofathle stem iszinsured, the; heat: being conductedlztterally-andlongitudinally: by the ineta l-lifii'tube 9, and; the fluid,- vapors85c; in: the-annular? chamber communioatingheat theret mandit will be;found thattho-temperature ofithe iriner tube 9, and-the;resulting-temperature; of the: stem: 1 will besubstantially; uniformthroughout, after a short BXposuroto the. heat of thofluid tobetested; 7

Asmalt tubular plug" 17 is threaded; into the lowerend: oftlie bore oilfthe plug 11, and through this the: lower portionof-the'the-rmometerstemextends, so; that the stern is held; and reinforced;therebyzi *A packing- 18,

of; any; suitable: compressible material is 1e sated between the;{extremities or? the; .tube' 9 and; the pIug'117',"so; that when,thesaid; parts 1 are serewedgupti'ght anefiective stnflingfwillbej'providede i 1 --i xvii-terminus; a r 1; 'Ina device:ofthe;eharactendescribed, the combination with a, thermomBl eKhaving Vabulb,,an elongated stem and ascale atits up teriorimmediately below thebottom: ofithe per portion, oft-a surrounding; and enclosing p g V I .7'structure'comprising atuberisurroundinggthe f The thermometer sten'ijl-ls wound-:wlth a steal; of-the thermometer, a rsecondftube;surrounding? said first named tube; ands-paced therefrom to provide anannular} chamber therebetween; said secon d. tube being: ada ted tested;for: temperature, and llaving: ope i at: itslower: partthrough whichthe: fluid ,passsfroel y? to. the interior ofsaid? tube and betweenitand' the firstnamed' tube;

' 2; In combination with the structuraspecifled in claim-'1', a-holl-owplugreceiving the ends" of the two; tubes "and having: a portioninterposed 3 therebetweeri to "secure 4 them; in

spaced relation, and? a second hollow plug threaded. into the lowerpart''ofi the: bore of the first hollow plug but having itsrupper end spacedfrom the lower end ofthe said first namedtubecfi 1 r 1 3. *Incombination with thestructure: specied into the lower part ofv the boreof the first hollow plug but having its upper end spaced from the lowerend of the said first named tube, a packing material within the bore ofthe first plug between the ends of the said second plug and the tube andsurrounding the 7 said stem. i

Witness my hand this 6th day of December, 1923, at the city of New York,in the 10 county and State of New York.

MAX E. MOELLER.

